亚洲毛亚洲丰满毛茸茸_国产亚洲女人久久久久久_新疆女人啪啪毛片_中文字幕视频人妻二区,亚洲av黄色,私人毛片高清影视免费看,五月天在线中文,www.黄网,久久人人97精品,欧美黄片免费日,日韩幻女BBWXXXX

Generally speaking, natural rubber refers to an elastic solid made from natural rubber latex collected from the Brazilian rubber tree through processing steps such as coagulation and drying. Natural rubber is a natural polymer compound with cis-1,4-polyisoprene as the main component. Its rubber hydrocarbon (cis-1,4-polyisoprene) content is above 90%. It also contains A small amount of protein, fatty acids, sugar and ash.